Surgical stapler

ABSTRACT

The present invention relates to an improved surgical stapler that prevents refiring of a spent staple cartridge. More specifically, this invention includes a simple, inexpensive mechanical locking mechanism which prevents refiring of a spent staple cartridge by blocking the path of the firing and/or cutting means of the stapler.

This is a continuation of application Ser. No. 08/038,587, filed Mar.26, 1993, still pending, which is a continuation of application Ser. No.07/855,183, filed Mar. 20, 1992, now U.S. Pat. No. 5,275,323, which is acontinuation of application Ser. No. 07/620,119, filed Nov. 30, 1990,now U.S. Pat. No. 5,129,570.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved surgical stapler thatprevents refiring of a spent staple cartridge. More specifically, thisinvention includes an inexpensive, simple and reliable mechanicallocking mechanism that prevents refiring of a spent staple cartridge.

2. Description of the Related Art

Before surgical staplers were introduced surgeons had to spend a greatdeal of time sewing the tissue of patients back together. This was themost time intensive aspect of a surgical procedure. Surgical staplershave decreased the amount of time that a user spends sewing tissue backtogether.

Another concern is whether the staplers used during procedures aresterile. Reusable staplers, being a relatively complicated mechanicalinstrument, are difficult to sterilize after use. Hence, it is desiredthat the surgical stapler be disposable. As more than one surgicalstapler may be required in a surgical procedure, for economical reasonsdisposable surgical staplers having reloadable staple cartridges havebeen developed.

It is desired that operating room personnel be able to quickly reload adisposable surgical stapler with an unspent staple cartridge during asurgical procedure. This is significant because as the amount of time ittakes to reload a stapler is decreased, the amount of time that thewhole procedure takes is also decreased. This means the amount of riskto the patient is less during a procedure of shorter duration. Forexample, the patient will not have to be under anesthesia as long duringa shorter procedure. However, delay occurs when a used cartridge isinadvertently reloaded in the stapler or a used cartridge is not removedbefore an attempt is made to use the stapler.

There are various types of staplers. Some staplers perform the solefunction of stapling while other types of staplers also performadditional functions. For example, one type of surgical stapler hasparallel rows of staples with a slot for a cutting means to travelbetween the rows of staples. This type of surgical stapler minimizesbleeding by applying the outside rows of staples to layers ofsurrounding tissue as the cutting means pierces through the tissue inbetween the staples. In such a stapler, if it is not recognized that aspent cartridge is in the stapler the user may attempt to cut tissuewithout the staples being inserted alongside the incision made by theknife.

As a result of the concern about such occurrences there have beenattempts made in the art to provide such disposable surgical staplerswith locking mechanisms that reduce possible delays or potential harm toa patient. Unfortunately, the locking mechanisms of these staplers arenot inexpensive, simple, or necessarily reliable.

For example, Green, U.S. Pat. No. 4,086,926 (hereinafter "Green")describes a stapler that has a cartridge that contains a means forlocking itself during shipment and preventing the inadvertent severingof organic structures when all of the staples, for example, have beenexpelled from the cartridge. Green describes a complex staple cartridgelocking system that is embodied in the cartridge. The Green cartridgeincludes the following; a rail assembly, an anvil means, an elongatemain body, a pair of belts mounted in the elongate main body, aplurality of surgical staples carried by the above-mentioned belts, apair of pushers, ramp means, a knife, and shifter means associated withthe knife. Since the cartridge has all these elements in it it iscomplex and relatively expensive to manufacture.

SUMMARY OF THE INVENTION

In accordance with the present invention a surgical stapler is providedfor applying a plurality of rows of staples housed in a disposablecartridge. The cartridge has a slot disposed between adjacent rows ofstaples that extends substantially the entire length of the rows ofstaples. The stapler includes firing means for the staples and a cuttingmeans movable in the slot. The cutting means has a bottom surface, a topsurface, and a cutting edge. The stapler also includes a lockingmechanism for preventing movement of the cutting means in the slot. Thelocking mechanism comprises a leaf spring disposed in the stapler thatengages the bottom surface of the cutting means to place the cuttingmeans in a first position. In the first position the cutting means isout of alignment with the slot. Also, there are means disposed on thecartridge for engaging the top surface of the cutting means. The meansfor engaging the top surface of the cutting means depresses the leafspring and moves the cutting means from the first position to a secondposition. In the second position the cutting means is in alignment withthe slot so the cutting means may move within the slot.

In one embodiment of the surgical stapler the means disposed on thecartridge for engaging the top surface of the cutting means is arotatable member which moves the cutting means from a first position toa second position.

In another embodiment of the surgical stapler the means disposed on thecartridge for engaging the top surface of the cutting means is aconfigured wire member that begins near the front of the cartridge slotand is disposed along substantially the entire length of the cartridgeslot to the rear of the staple cartridge. This embodiment includescavities molded in the staple cartridge which cooperate with the wiremember to move the cutting means from a first position to a secondposition.

In yet another embodiment of the surgical stapler the means disposed onthe cartridge for engaging the top surface of the cutting means is abreakable member. The member is broken upon moving the cutting meansfrom the first position to the second position.

The preferred embodiments of the surgical staplers of the presentinvention have two adjacent rows of staples on each side of thecartridge slot. Also, in the preferred embodiments the cutting means isa knife blade assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a surgical stapler of thepresent invention;

FIG. 2 is an exploded perspective view with parts of the lockingmechanism broken away;

FIG. 3 is a side elevational view in partial cross-section prior to theinsertion of the staple cartridge and showing the cutting means in alocked first position;

FIG. 4 is an enlarged detail view in partial cross-section showing thelocking mechanism locking the cutting means in the first position;

FIG. 5 is a view similar to that of FIG. 3 with a staple cartridge inplace;

FIG. 6 is an enlarged detail view in partial cross section showing theknife blade assembly in the second position;

FIG. 7 is a top plan view taken along view line 7--7 of FIG. 6 showingthe knife blade assembly prior to firing of the staple cartridge;

FIG. 8 is a top plan view of the assembly as shown in FIG. 7 afterfiring of the staples and knife blade assembly showing the broken meansdisposed on the cartridge of one embodiment of the invention;

FIG. 9 is a perspective view of a locking mechanism of anotherembodiment of the present invention;

FIG. 10 is a top plan view similar to FIG. 7 showing the embodiment asdepicted in FIG. 9;

FIG. 11 is a schematic side elevational view showing yet anotherembodiment of a locking mechanism of the present invention in partialcross-section when the knife blade assembly is moving forward throughthe cartridge slot of a staple cartridge containing staples;

FIG. 12 is a schematic side elevational view showing the embodimentdepicted in FIG. 11 in partial cross-section when the knife bladeassembly is moving backward through the cartridge slot of a staplecartridge that no longer contains staples; and

FIG. 13 is a top plan view similar to FIG. 10 showing the embodimentdepicted in FIG. 11.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Reference will now be made in detail to specific embodiments of thepresent invention which are conveniently described by reference to theaccompanying FIGS. 1-13.

As seen in FIG. 1, a typical surgical stapler 20 comprises an upperpiece 30, a firing means 40, a lower piece 50 and a staple cartridge 60.

Staple cartridge 60 fits within the lower piece 50. Specifically, thefront part of staple cartridge 60 fits into lower jaw channel 54. Morespecifically, the parallel side walls 61 of the staple cartridge 60 fitwithin the lower jaw channel 54. The back part of staple cartridge 60has a breakable transverse member 66. This breakable transverse member66 is placed on top of cartridge locking means 47 of firing means 40. Atthe same time two legs 65 secure staple cartridge 60 to lower piece 50.These legs 65 engage cylinder 58 of lower piece 50 in the secondposition, as best seen in FIG. 2.

In FIG. 1 the upper piece 30 has a rear upper handle portion 31 and afront upper jaw portion 32. Likewise, the lower piece 50 includes a rearmovable lower handle portion 51 and a front lower jaw portion 53. Theembodiment of the surgical stapler 20 illustrated in FIGS. 1-13incorporates the firing means 40, leaf spring 57, and staple cartridge60 into the lower piece 50. Yet, these elements may be placed in theupper piece 30 instead of lower piece 50.

The lower handle portion 51 illustrated in FIG. 1 is movable, morespecifically, pivotable between two locking positions. In the firstlocking position the movable lower handle portion 51 is positioned at anoblique angle to the lower jaw portion 53. During the first lockingposition a C-shaped member 52 of the lower handle 51 is disengaged froma stationary locking pin 33. The upper and lower pieces, 30 and 50,respectively may be separated before or after operation of stapler 20 inthe first locking position. On the other hand, in the second lockingposition the C-shaped member 52 of the movable lower handle 51 locks theupper and lower pieces 30 and 50 together. In the second lockingposition the movable lower handle portion 51 is parallel to the lowerjaw portion 52. This second locking position occurs by engagingstationary locking pin 33 with C-shaped member 52. This movable handleportion design may be on the upper or lower handle portions, 31 and 51,respectively.

The firing means 40 will generally comprise at least one pusher bar 42,as best seen in FIG. 2. Firing knob 59 in FIG. 1 activates firing means40 by moving pusher bars 42 through staple cartridge 60 during thesecond position. The firing means 40 of the present invention alsoincludes a roof assembly 70.

The various elements of roof assembly 70 are illustrated in FIG. 2. Roofassembly 70 has a narrow roof portion 71 near the front of stapler 20.That narrow roof portion 71 is integral with a widened roof portion 72.Widened roof portion 72 has three slits. Knife slit 73 runs through bothwidened roof portion 72 and narrow roof portion 71. Widened roof portion72 contains two more slits than narrow roof portion 71. The twoadditional slits in widened roof portion 72 are pusher bar slits 74. Thewidth of narrow roof portion 71 is less than the transverse distancebetween the two pusher bars 42. So, pusher bars 42 may slide around andpast narrow roof portion 71 toward the longitudinal slots 63 of staplecartridge 60. The two outer pusher bar slits 74 of the widened roofportion 72 can accommodate the two pusher bars 42. As pusher bars 42slide through pusher bar slits 74 knife blade assembly 44 is movingforward in the second position.

Returning to FIG. 1, the firing means 40 will also contain a cuttingmeans. Specifically, the cutting means is a knife blade assembly 44. Acutting surface 45 is included in knife blade assembly 44. Cuttingsurface 45 is illustrated in FIGS. 1-8. Generally, knife blade assembly44 is placed between the pusher bars 42. Although a knife blade assemblyis illustrated in FIGS. 1-13 tissue may be cut in many ways besidesknife or razor blade cutting. For example, laser or chemical destructionof tissue or tearing are just a few cutting means that may be used.These and other means of cutting tissue should be considered within thescope of the present invention.

In the first position the knife blade assembly 44 is out of alignmentwith slot 64. In the second position knife blade assembly 44 is inalignment with slot 64. The operation of this surgical stapler 20 issimilar to the operation of the surgical stapler disclosed in commonlyassigned U.S. Pat. No. 4,892,244, (Fox et al.), issued Jan. 9, 1990,hereby incorporated by reference.

The knife blade assembly 44 shown in FIGS. 2, 3, and 4 is locked in thefirst position. In the first position leaf spring 57 pushes knife bladeassembly 44 up against roof assembly 70. This is best illustrated by thearrow in FIG. 4. The upward force of knife blade assembly 44 keepswidened roof portion 72 wedged in knife locking means area 46. As seenin FIGS. 3 and 4 the upward pressure of leaf spring 57 raises rooflocking portion 48 to a height at which it cannot move beyond the rearof widened roof portion 72. This is true even if firing knob 59 ispushed forward in an attempt to operate stapler 20. In this firstposition knife blade assembly 44 cannot be moved. The two parallelpusher bars 42 cannot be moved either in the first position. Therefore,the two parallel pusher bars 42 cannot dislodge staples 80 from a fullstaple cartridge 60 when the knife blade assembly 44 is in the firstposition.

When the knife blade assembly 44 is being placed in the second positionthe user will hear a click as a full staple cartridge 60 is mounted.Staple cartridge 60 is mounted on lower piece 50 by engaging legs 65 ofstaple cartridge 60 with cylinder 58 of lower piece 50. FIG. 7illustrates this point in time at which breakable transverse member 66is still intact. The new staple cartridge 60 also has staples 80 inlongitudinal slots 63 at this time. This same point in time is beforestaples 80 are fired from staple cartridge 60 and is shown in FIGS. 5and 6. Breakable transverse member 66, seen in FIGS. 5 and 6, exerts adownward force upon cartridge locking means 47. This downward forcepushes down the entire knife blade assembly 44 as well as leaf spring 57which is below knife blade assembly 44. When this happens knife bladeassembly 44 is unlocked. So, as best illustrated in FIG. 6, the user maypush the firing knob 59 toward staple cartridge 60. Pushing firing knob59 will move knife blade assembly 44 forward. When knife blade assembly44 is unlocked the knife locking means 46 is no longer wedged under thewidened roof portion 72 of roof assembly 70.

Next, knife blade assembly 44 may be moved toward the staple cartridge60. As knife blade assembly 44 is moved transverse member breakingportion 49 breaks the breakable transverse member 66. Then the knifecutting surface 45 is moved through slot 64 of staple cartridge 60. Thetwo pusher bars 42 simultaneously remove staples 80 from staplecartridge 60. The stage after breakable transverse member 66 is brokenis shown in FIG. 8. Completion of the stapling operation is illustratedby the absence of staples 80 in longitudinal slots 63. Also, breakabletransverse member 66 is permanently broken so there is no way that aused staple cartridge 60' is effectively reusable.

Comparison of FIGS. 4 and 6 highlights the interaction of various partsof knife blade assembly 44 in the first position (FIG. 4) and the secondposition (FIG. 6). FIG. 6 is similar to FIG. 4 except that FIG. 6includes staple cartridge 60. For example, in FIG. 6 legs 65 of staplecartridge 60 are shown in phantom. The legs 65 wrap around cylinder 58.The force exerted downward by breakable transverse member 66 is greaterthan the force exerted upward by leaf spring 57 in the second position.So, as a result of the force exerted by breakable transverse member 66roof locking portion 48 has a height lower than roof assembly 70.Therefore, roof locking portion 48 no longer prohibits forward movementof knife blade assembly 44 in the second position.

Parts of the next embodiment that are the same as those of theembodiment discussed above will be referred to with the same last twodigits as the corresponding parts of the previous embodiment except theywill be preceded by the number 1. Another embodiment of this inventionis illustrated in FIGS. 9 and 10.

The embodiment of FIGS. 9 and 10 has a rotatable member 167 that is atoggle type gate. Rotatable member 167 is affixed to a first parallelrearwardly extending surface 162a. An unused staple cartridge 160 has arotatable member 167 that extends transversely across knife assembly 144toward the second parallel rearwardly extending surface 162b. In thesecond position rotatable member 167 performs the same function asbreakable transverse member 66 by depressing knife blade assembly 144.The rotatable member 167 is shown in the second position engagingcartridge locking means 147. When the rotatable member engages cartridgelocking means 147 it depresses leaf spring 157. After leaf spring 157 isdepressed knife blade assembly 144 may be moved toward staple cartridge160.

The arrow in FIG. 9 shows how rotatable member 167 is rotated to theside when knife blade assembly 144 is moved forward toward staplecartridge 160. Rotatable member 167 is parallel to knife blade assembly144 in the first position. This is shown in phantom in FIGS. 9 and 10.

Parts of the next embodiment that are the same as those of the firstembodiment discussed above will be referred to with the same last twodigits as the corresponding parts of the first embodiment discussedexcept they will be preceded by the number 2. Yet another embodiment ofthis invention is illustrated in FIGS. 11, 12 and 13 which requires thata configured wire member 268 be in staple cartridge 260. This embodimentalso requires that two cavities 269a and 269b be molded into the twoparallel rearwardly extending surfaces 262a and 262b.

FIG. 13 shows that the configured wire member 268 extends alongsubstantially the entire length of cartridge slot 264 into the firstcavity 269a. Then the configured wire member 268 extends along the firstparallel rearwardly extending surface 262a. Next, configured wire member268 extends across the top surface of cartridge locking means 247. Afterthat, configured wire member 268 extends along the second parallelrearwardly extending surface 262b. Finally, the configured wire member268 extends into and out of the second cavity 269b to its terminationalong the front of the second parallel rearwardly extending surface262b.

FIG. 11 illustrates this embodiment in the second position. In FIG. 11configured wire member 268 engages the top surface of knife bladeassembly 244. Configured wire member 268 does this at cartridge lockingmeans 247. The arrow in FIG. 11 indicates that knife blade assembly 244can move forward. Knife blade assembly 244 can move forward becauseconfigured wire member 248 is pressing down knife blade assembly 244.The comparison of FIGS. 4 and 6 with respect to the first embodimentdescribed applies to a comparison of FIGS. 11 and 12 of the embodimentjust described.

FIG. 12 illustrates configured wire member 268 in the first positionwhen it cannot hold down the top surface of cartridge locking means 247.The configured wire member 268' shown in phantom in FIG. 13 is releasedfrom the cavities 269a and 269b. As a result, it does not exertsufficient downward force upon knife blade assembly 244 to counteractthe upward force of leaf spring 257. Therefore, it is necessary to placea fresh staple cartridge 260 in the stapler 220. That is, if theoperator desires to return the stapler 220 to the second position inwhich the knife blade assembly 244 is movable.

The unique combination of features possessed by the present inventionrender them well suited for use within a surgical stapler, in order toprevent refiring or reloading of a spent surgical staple cartridge. Thisenhances speed and time of performance for the surgeon. Naturally, thesecombinations may be useful for other types of cartridge-loadingmechanisms. Of course, while several means are available, the particularadvantageous embodiments have been chosen to illustrate the invention.It will be understood by those skilled in the art that various changesand modifications may be made in the invention without departing fromits scope, which is defined by the following claims and theirequivalents.

What is claimed is:
 1. A surgical stapler comprising:a cartridge having a plurality of rows of staples disposed along a longitudinal axis of said cartridge; at least one pusher bar movable distally within said cartridge for ejecting said staples; a lockout member movable distally in said stapler, said lockout member being further movable generally perpendicularly to the direction of distal movement of said lockout member; and a barrier engageable by said lockout member in a retracted position of said lockout member, subsequent to an initial distal movement of said lockout member.
 2. A surgical stapler in accordance with claim 1, wherein said lockout member comprises an elongated member having a notched surface.
 3. The stapler of claim 1 wherein said barrier comprises a first surface extending generally transversely to said longitudinal axis for engagement by said lockout member.
 4. A surgical stapler in accordance with claim 1, further comprising a knife.
 5. A surgical stapler in accordance with claim 1 wherein said lockout member comprises a knife blade.
 6. A surgical stapler in accordance with claim 1 further including a stop member comprising a roof assembly.
 7. A surgical stapler in accordance with claim 1, wherein said lockout member is spring biased generally perpendicularly to the direction of distal movement thereof toward a position for engaging said barrier.
 8. A surgical stapler in accordance with claim 7, wherein said lockout member is biased by a leaf spring.
 9. A surgical stapler in accordance with claim 1, further comprising a movable restraint on said stapler engaged with said lockout member during a portion of the distal movement of said lockout member.
 10. A surgical stapler in accordance with claim 9, wherein said restraint comprises a rotatable member.
 11. A surgical stapler in accordance with claim 9, wherein said lockout member is spring biased generally perpendicularly to the direction of distal movement thereof toward a position for engaging said barrier, said restraint acting to prevent engagement of said lockout member with said barrier prior to at least a portion of a distal movement of said lockout member.
 12. A surgical stapler comprising:a frame means and a cartridge having a plurality of rows of staples defining a longitudinal axis of said stapler; firing means movable relative to said frame means to fire the staples along said axis; and a lockout mechanism for preventing a subsequent longitudinal firing movement of the firing means after at least a portion of said firing means has been moved to a retracted longitudinal position opposite to a direction of firing movement of said firing means, said lockout mechanism comprising a lockout member movable distally within said stapler and movable generally perpendicular to the direction of distal movement from a first position to a second position, a restraint for maintaining said lockout member in said first position thereof during at least a portion of a distal movement of said lockout member so that said firing means fires said staples, said restraint being movable in response to firing movement of said firing means so that said lockout member is moved to said second position to prevent refiring after at least a portion of said firing means moves to said retracted position.
 13. A surgical stapler of claim 12 further comprising a knife blade.
 14. A surgical stapler in accordance with claim 12, wherein said restraint comprises a member movably mounted on said stapler.
 15. A surgical stapler in accordance with claim 14, wherein said movably mounted member is rotatable.
 16. A surgical stapler in accordance with claim 12, wherein said lockout member comprises a notched surface engageable with a barrier for preventing subsequent longitudinal movement of said firing means.
 17. A surgical stapler in accordance with claim 16, wherein said lockout member is located on said knife blade.
 18. A surgical stapler comprising:a cartridge having a plurality of rows of staples disposed along a longitudinal axis of said cartridge; at least one pusher bar movable distally within said cartridge for ejecting said staples; a lockout member movable distally in said stapler, said lockout member being further movable generally perpendicularly to the direction of distal movement of said lockout member; and a barrier member engageable by said lockout member in a retracted position of said lockout member, subsequent to an initial distal movement of said lockout member; and wherein said lockout member is spring biased generally perpendicularly to the direction of distal movement thereof toward a position for engaging said barrier, said restraint acting to prevent engagement of said lockout member with said barrier prior to at least a portion of a distal movement of said lockout member.
 19. A surgical stapler for applying a plurality of rows of staples, said rows of staples being housed in a disposable cartridge having a front portion and a rear portion, said cartridge having a cartridge slot disposed between adjacent rows of staples and extending substantially the entire length of said rows, said stapler including firing means for said staples, cutting means movable in said slot and a locking mechanism for preventing movement of said cutting means in said slot, said cutting means having a bottom surface, a top surface, and a cutting edge, said locking mechanism comprising a leaf spring disposed in said stapler and engaging the bottom surface of said cutting means, to place said cutting means in a first position out of alignment with said slot, means disposed on said cartridge for engaging the top surface of the cutting means to depress said leaf spring and move said cutting means from said first position to a second position in alignment with said slot whereby said cutting means may move within said slot. 